US President Donald Trump removed his chief strategist Steve Bannon from the National Security Council on Wednesday, reversing his controversial decision earlier this year to give a political adviser an unprecedented role in security discussions.

Trump's overhaul of the NSC, confirmed by a White House official, also elevated General Joseph Dunford, chairman of the Joint Chiefs of Staff and Dan Coats, director of National Intelligence who heads all 17 US intelligence agencies. The official said the change moves the NSC "back to its core function of what it’s supposed to do".

It also appears to mark a victory for national security adviser HR McMaster, who had told some national security experts he felt he was in a "battle to the death" with Bannon and others on the White House staff.

However, the effects of the reshuffle are unknown at this point. Bannon runs a parallel White House security committee named the Strategic Initatives Group, with security analysts calling it a “shadow NSC” that’s “more secretive and unaccountable”.

Trump's White House team has grappled with infighting and palace intrigue that has hobbled his nascent presidency. In recent days, several other senior US foreign policy and national security officials have said the mechanisms for shaping the Trump administration's response to pressing challenges such as Syria, North Korea and Iran were still not in place.

Trump's elevation of Bannon to a permanent spot on the NSC had been widely criticised as injecting politics into White House deliberations on sensitive defence, foreign policy and intelligence matters.

The move revealed on Wednesday was seen as a setback for Bannon, the controversial former head of the far-right media website Breitbart, who is one of Trump's most trusted advisers and sometimes dubbed the real power in the White House.

Susan Rice operationalized the NSC during the last administration so I was put on NSC to ensure it was 'de-operationalized.'

- Steve Bannon, White House chief strategist

Trump made no statement on the shift, but Bannon described it as part of a process of getting the council under control after it grew rapidly under president Barack Obama's national security adviser, Susan Rice.

"Susan Rice operationalized the NSC during the last administration so I was put on NSC to ensure it was 'de-operationalized.' General McMaster has NSC back to its proper function," Bannon said in a statement.

Bannon represents Trump's "America First" nationalistic voice, helping fuel his anti-Washington fervour and pushing for the president to part ways when he needs to with the establishment wing of the Republican Party.

US Representative Adam Schiff, ranking Democrat on the House of Representatives intelligence committee, called the shift in the NSC a positive step that will help McMaster "gain control over a body that was being politicised by Bannon's involvement."

"As the administration's policy over North Korea, China, Russia and Syria continues to drift, we can only hope this shake-up brings some level of strategic vision to the body," he said.

A White House official said Bannon was no longer needed on the NSC after the departure of Trump's first national security adviser, Michael Flynn.

The official said Bannon had been placed on the NSC originally as a check on Flynn and had only ever attended one of the NSC's regular meetings.

However, two current national security officials rejected the White House explanation, noting that two months have passed since Flynn's departure.

McMaster, they said, speaking on the condition of anonymity, also has duelled with Bannon and others over direct access to Trump; the future of deputy national security adviser KT McFarland, a former Fox News commentator; intelligence director Ezra Cohen-Watnick, a Flynn appointee, and other staffing decisions.

Trump is preparing for his first face-to-face meetings on Thursday and Friday with Chinese President Xi Jinping, with the threat of North Korea's nuclear and missile programmes a key component of their talks.

Bannon's seat on the NSC's "principals' committee," a group that includes the secretaries of state, defence and other ranking aides, was taken by Rick Perry, who as energy secretary is charged with overseeing the US nuclear weapons arsenal.